Children are increasingly becoming an important segment of the nation's obese population and the impact of excess adiposity on the long-term health of children may exceed that of their adult counterparts. The study of adipose tissue (AT) metabolic activity and distribution provides insights into health-associated risks of pediatric obesity. In adults, although total body AT mass may be large, only specific relatively small, highly-active compartments are strongly associated with morbidity. Visceral adipose tissue (VAT), the most studied of these compartments, is central to phenotyping humans for obesity. Reference methods for measuring the amount of VAT, are magnetic resonance imaging (MRI) and computed tomography (CT). CT is of limited use in pediatrics because of the associated radiation exposure. The characterization and measurement of AT compartments in children poses special problems. VAT has traditionally been estimated from a single cross-sectional area at the L4-L5 intervertebral space. Recent studies suggest that intraperitoneal AT, consisting mainly of mental and mesenteric AT, is the component that most strongly links adiposity with adverse health consequences. However, there may be little or no intraperitoneal AT at the L4-L5 level in children, although deposits may be found at anatomical levels higher than L4-L5, in the upper abdomen. Our recent studies in a large sample of adults showed that an image slice at 5 to 10 cm above the L4-L5 level best represents total VAT volume. Another concern is that whole-body VAT and other regional AT components may not be accurately measured in children using current adult MRI protocols that include a "gap" (e.g., 4 cm) between images. These limitations on evaluating regional adiposity, especially VAT, in children, prompted the present proposed investigation. Our proposed aim is to assemble and analyze a database of existing subject-diverse whole-body MRI scans of children, including a unique subset of contiguous-slice scans, to identify and propose solutions to the unique adiposity imaging challenges posed by children. The assembled database will allow us to test important hypotheses related to measurement methods, imaging model development, and health risks in children. Our findings could potentially set standards for the evaluation of total body and regional AT in pediatrics, and improve study power.